Compliance to Screening Protocols for Multidrug-Resistant Microorganisms at the Emergency Departments of Two Academic Hospitals in the Dutch-German Cross-Border Region

Infections caused by multidrug-resistant organisms (MDROs) are associated with prolonged hospitalization and higher risk of mortality. Patients arriving in the hospital via the emergency department (ED) are screened for the presence of MDROs in compliance with the screening protocols in order to apply the correct isolation measures. In the Dutch-German border region, local hospitals apply their own screening protocols which are based upon national screening protocols. The contents of the national and local MDRO screening protocols were compared on vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and carbapenemase-producing and carbapenem-resistant Enterobacteriaceae (CPE/CRE). The practicality of the screening protocols was evaluated by performing an audit. As a result, the content of the MDRO screening protocols differed regarding risk factors for MDRO carriage, swab site, personal protective equipment, and isolation measures. The observations and questionnaires showed that the practicality was sufficient; however, the responsibility was not designated clearly and education regarding the screening protocols was deemed inappropriate. The differences between the MDRO screening protocols complicate patient care in the Dutch-German border region. Arrangements have to be made about the responsibility of the MDRO screening, and improvements are necessary concerning education regarding the MDRO screening protocols

Genetic loci of Staphylococcus aureus associated with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides

The proteinase 3 (PR3)-positive anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) granulomatosis with polyangiitis (GPA) has been associated with chronic nasal S. aureus carriage, which is a risk factor for disease relapse. The present study was aimed at comparing the genetic make-up of S. aureus isolates from PR3-ANCA-positive GPA patients with that of isolates from patients suffering from myeloperoxidase (MPO)-ANCA-positive AAV, and isolates from healthy controls. Based on a DNA microarray-based approach, we show that not only PR3-ANCA-positive GPA patients, but also MPO-ANCA-positive AAV patients mainly carried S. aureus types that are prevalent in the general population. Nonetheless, our data suggests that MPO-ANCA-associated S. aureus isolates may be distinct from healthy control- and PR3-ANCA-associated isolates. Furthermore, several genetic loci of S. aureus are associated with either PR3-ANCA- or MPO-ANCA-positive AAV, indicating a possible role for pore-forming toxins, such as leukocidins, in PR3-ANCA-positive GPA. Contrary to previous studies, no association between AAV and superantigens was detected. Our findings also show that a lowered humoral immune response to S. aureus is common for PR3-ANCA- and MPO-ANCA-positive AAV. Altogether, our observations imply that the presence or absence of particular virulence genes of S. aureus isolates from AAV patients contributes to disease progression and/or relapse

Low anti-staphylococcal IgG responses in granulomatosis with polyangiitis patients despite long-term Staphylococcus aureus exposure

Chronic nasal carriage of the bacterium Staphylococcus aureus in patients with the autoimmune disease granulomatosis with polyangiitis (GPA) is a risk factor for disease relapse. To date, it was neither known whether GPA patients show similar humoral immune responses to S. aureus as healthy carriers, nor whether specific S. aureus types are associated with GPA. Therefore, this study was aimed at assessing humoral immune responses of GPA patients against S. aureus antigens in relation to the genetic diversity of their nasal S. aureus isolates. A retrospective cohort study was conducted, including 85 GPA patients and 18 healthy controls (HC). Humoral immune responses against S. aureus were investigated by determining serum IgG levels against 59 S. aureus antigens. Unexpectedly, patient sera contained lower anti-staphylococcal IgG levels than sera from HC, regardless of the patients' treatment, while total IgG levels were similar or higher. Furthermore, 210 S. aureus isolates obtained from GPA patients were characterized by different typing approaches. This showed that the S. aureus population of GPA patients is highly diverse and mirrors the general S. aureus population. Our combined findings imply that GPA patients are less capable of mounting a potentially protective antibody response to S. aureus than healthy individuals

Novel Twin-Arginine Translocation Pathway-Dependent Phenotypes of Bacillus subtilis Unveiled by Quantitative Proteomics

<p>The twin-arginine translocation (Tat) pathway is known to translocate fully folded proteins across bacterial, archaeal, and organellar membranes. To date, the mechanisms involved in processing, proofreading, and quality control of Tat substrates have remained largely elusive. Bacillus subtilis is an industrially relevant Gram-positive model bacterium. The Tat pathway in B. subtilis differs from that of other well-studied organisms in that it is composed of two complexes operating in parallel. To obtain a better understanding of this pathway in B. subtilis and to identify Tat-associated proteins, the B. subtilis 'Tat proteome' was investigated by quantitative proteomics. Metabolically labeled proteins from cytoplasmic, membrane, and extracellular fractions were analyzed by LC MS/MS. Changes in the amounts of identified peptides allowed for quantitative comparisons of their abundance in tat mutant strains. The observed differences were suggestive of indirect or direct protein protein relationships. The rich data set generated was then approached in hypothesis-driving and hypothesis-driven manners. The hypothesis-driving approach led to the identification of a novel delayed biofilm phenotype of certain tat mutant strains, whereas the hypothesis-driven approach identified the membrane protein QcrA as a new Tat substrate of B. subtilis. Thus, our quantitative proteomics analyses have unveiled novel Tat pathway-dependent phenotypes in Bacillus.</p>

Novel Twin-Arginine Translocation Pathway-Dependent Phenotypes of <i>Bacillus subtilis</i> Unveiled by Quantitative Proteomics

The twin-arginine translocation (Tat) pathway is known to translocate fully folded proteins across bacterial, archaeal, and organellar membranes. To date, the mechanisms involved in processing, proofreading, and quality control of Tat substrates have remained largely elusive. <i>Bacillus subtilis</i> is an industrially relevant Gram-positive model bacterium. The Tat pathway in <i>B. subtilis</i> differs from that of other well-studied organisms in that it is composed of two complexes operating in parallel. To obtain a better understanding of this pathway in <i>B. subtilis</i> and to identify Tat-associated proteins, the <i>B. subtilis</i> 'Tat proteome' was investigated by quantitative proteomics. Metabolically labeled proteins from cytoplasmic, membrane, and extracellular fractions were analyzed by LC–MS/MS. Changes in the amounts of identified peptides allowed for quantitative comparisons of their abundance in <i>tat</i> mutant strains. The observed differences were suggestive of indirect or direct protein–protein relationships. The rich data set generated was then approached in hypothesis-driving and hypothesis-driven manners. The hypothesis-driving approach led to the identification of a novel delayed biofilm phenotype of certain <i>tat</i> mutant strains, whereas the hypothesis-driven approach identified the membrane protein QcrA as a new Tat substrate of <i>B. subtilis</i>. Thus, our quantitative proteomics analyses have unveiled novel Tat pathway-dependent phenotypes in <i>Bacillus</i>

Novel Twin-Arginine Translocation Pathway-Dependent Phenotypes of <i>Bacillus subtilis</i> Unveiled by Quantitative Proteomics

The twin-arginine translocation (Tat) pathway is known to translocate fully folded proteins across bacterial, archaeal, and organellar membranes. To date, the mechanisms involved in processing, proofreading, and quality control of Tat substrates have remained largely elusive. <i>Bacillus subtilis</i> is an industrially relevant Gram-positive model bacterium. The Tat pathway in <i>B. subtilis</i> differs from that of other well-studied organisms in that it is composed of two complexes operating in parallel. To obtain a better understanding of this pathway in <i>B. subtilis</i> and to identify Tat-associated proteins, the <i>B. subtilis</i> 'Tat proteome' was investigated by quantitative proteomics. Metabolically labeled proteins from cytoplasmic, membrane, and extracellular fractions were analyzed by LC–MS/MS. Changes in the amounts of identified peptides allowed for quantitative comparisons of their abundance in <i>tat</i> mutant strains. The observed differences were suggestive of indirect or direct protein–protein relationships. The rich data set generated was then approached in hypothesis-driving and hypothesis-driven manners. The hypothesis-driving approach led to the identification of a novel delayed biofilm phenotype of certain <i>tat</i> mutant strains, whereas the hypothesis-driven approach identified the membrane protein QcrA as a new Tat substrate of <i>B. subtilis</i>. Thus, our quantitative proteomics analyses have unveiled novel Tat pathway-dependent phenotypes in <i>Bacillus</i>

Genetic loci of Staphylococcus aureus associated with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides

Abstract The proteinase 3 (PR3)-positive anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) granulomatosis with polyangiitis (GPA) has been associated with chronic nasal S. aureus carriage, which is a risk factor for disease relapse. The present study was aimed at comparing the genetic make-up of S. aureus isolates from PR3-ANCA-positive GPA patients with that of isolates from patients suffering from myeloperoxidase (MPO)-ANCA-positive AAV, and isolates from healthy controls. Based on a DNA microarray-based approach, we show that not only PR3-ANCA-positive GPA patients, but also MPO-ANCA-positive AAV patients mainly carried S. aureus types that are prevalent in the general population. Nonetheless, our data suggests that MPO-ANCA-associated S. aureus isolates may be distinct from healthy control- and PR3-ANCA-associated isolates. Furthermore, several genetic loci of S. aureus are associated with either PR3-ANCA- or MPO-ANCA-positive AAV, indicating a possible role for pore-forming toxins, such as leukocidins, in PR3-ANCA-positive GPA. Contrary to previous studies, no association between AAV and superantigens was detected. Our findings also show that a lowered humoral immune response to S. aureus is common for PR3-ANCA- and MPO-ANCA-positive AAV. Altogether, our observations imply that the presence or absence of particular virulence genes of S. aureus isolates from AAV patients contributes to disease progression and/or relapse

Low anti-staphylococcal IgG responses in granulomatosis with polyangiitis patients despite long-term Staphylococcus aureus exposure

textabstractChronic nasal carriage of the bacterium Staphylococcus aureus in patients with the autoimmune disease granulomatosis with polyangiitis (GPA) is a risk factor for disease relapse. To date, it was neither known whether GPA patients show similar humoral immune responses to S. aureus as healthy carriers, nor whether specific S. aureus types are associated with GPA. Therefore, this study was aimed at assessing humoral immune responses of GPA patients against S. aureus antigens in relation to the genetic diversity of their nasal S. aureus isolates. A retrospective cohort study was conducted, including 85 GPA patients and 18 healthy controls (HC). Humoral immune responses against S. aureus were investigated by determining serum IgG levels against 59 S. aureus antigens. Unexpectedly, patient sera contained lower anti-staphylococcal IgG levels than sera from HC, regardless of the patients' treatment, while total IgG levels were similar or higher. Furthermore, 210 S. aureus isolates obtained from GPA patients were characterized by different typing approaches. This showed that the S. aureus population of GPA patients is highly diverse and mirrors the general S. aureus population. Our combined findings imply that GPA patients are less capable of mounting a potentially protective antibody response to S. aureus than healthy individuals